This is a Shannon award providing partial support for the research projects that fall short of the assigned Institute's funding range but are in the margin of excellence. The Shannon award is intended to provide support to test the feasibility of the approach; develop further tests and refine research techniques; perform secondary analysis of available data sets; or conduct discrete projects that can demonstrate the PI's research capabilities or lend additional weight to an already meritorious application. The abstract below is taken from the original document submitted by the principal investigator. DESCRIPTION (Adapted from applicant's abstract): This a revised application to study the molecular basis of Stickler syndrome (arthro- ophthalmopathy), an autosomal dominant connective tissue disorder with visual symptoms of progressive myopia, vitreo-retinal degeneration and retinal detachments. Two nonsense mutations and a nucleotide deletion leading to a premature stop codon in the type II procollagen gene (COL2A1) have been identified by the applicant. Several additional mutations in COL2A1 were found in Stickler syndrome and other related disorders. This proposal focuses on the molecular and biochemical basis of Stickler syndrome as encompassed in three specific aims. Aim 1 is to screen additional Stickler syndrome families for mutations at the COL2A1 locus using linkage, heteroduplex, and direct sequence analysis. Aim 2 is to determine the consequences of identified mutations through the analysis of stably-transfected cell lines expressing mutant and normal type II procollagen. Aim 3 is to create transgenic mouse models of Stickler syndrome using gene knockout embryonic stem cell technology or through the introduction of more subtle mutations using cassette replacement "in/out" targeting. The conformational integrity and fibril assembly of the expressed protein from the transfection and transgenic experiments will be examined as well as effects on mRNA production, stability, and composition.